1. Field of the Invention
The present invention relates to an information recording apparatus including an actuator which has a head arm for holding a recording/reproducing head for a recording medium and which loads and unloads the head arm for the recording medium by swinging. More particularly, the present invention relates to an information recording apparatus including a function for preventing the actuator from being swung accidentally toward the recording medium side when the apparatus is subjected to an external shock in a state that the actuator is located at a shunt position.
2. Description of the Related Art
As a shunt position of an actuator at non-operating, a ramp block is arranged on a periphery of a disc. Holding the actuator on the ramp block prevents a slider from moving accidentally to a data area of the disc. This is done to avoid adsorbing the slider onto the disc surface during stoppage or damaging the data area.
It is required that the actuator is held at a shunt position also when the apparatus is subjected to an external shock at non-operating. In particular, in a magnetic disc apparatus carried on a portable personal computer such as a notebook computer, a high reliability to cope with the shock is required at non-operating.
As measures against a shock, it is considered to provide an inertia lever and a latch lever. When the apparatus is subjected to an external shock, the inertia lever is swung by the inertia, the swung inertia lever is engaged with the latch lever, and the latch lever is caused to move to a swing locus of the actuator, thereby latching the actuator by the latch lever. This holds the actuator at a shunt position in spite of the shock. This function is exhibited in a clockwise direction or in a counterclockwise direction.
On the other hand, the actuator may excessively swing in a load direction or in an unload direction exceeding a limit of its original swing range due to some unusual condition such as an abnormal run of a voice coil motor during the operation of the apparatus. At this time, in order to prevent the actuator from hitting a spindle motor or other areas of the apparatus, crush stops are provided. The crush stops has two ones: one in a load direction side; and another in an unload direction side.
In order to restrain the accidental swing of the actuator due to a shock, using two elements of the inertia lever and the latch lever causes the reliability of operation to become unstable.
The inertia lever has a lager mass than that of the latch lever, so that the inertia lever, when subjected to a shock, swings earlier than the latch lever. The latch lever having a smaller mass swings later.
There is a time difference in the start of swing between both levers as described above, and the actuator is not engaged with the latch lever in a stationary state at the shunt position. This brings about a possibility that the latch operation of the actuator by the latch lever fails. In particular, when the actuator hits the crush stops, thus causing a rebound thereof, there becomes higher a possibility that the latch operation fails.
The fact that the latch mechanism consists of two elements of the inertia lever and the latch lever to cause the each structure to become complex, and that two crush stops are required, as a whole, leads to an increased structural complex and an increased cost.
Although the above-mentioned problems are associated with a magnetic disc apparatus, the problems can be addressed by applying them not only to a case where the recording medium is a magnetic disc, but also widely to general information recording apparatuses.
Therefore, an object of the present invention is to provide an information recording apparatus wherein an actuator can securely be held at a shunt position against an external shock.
Another object of the present invention is provide an information recording apparatus which can prevent the actuator from swinging excessively due to some unusual conditions such as an abnormal run of a voice coil motor.
A further object of the present invention is to provide an information recording apparatus wherein the number of parts is reduced to thereby achieve a slim shape.
Other objects, features and advantages of the present invention will appear in the description thereof which follows.
The actuator has a head arm for holding a recording/reproducing head for a recording medium, and loads and unloads the head arm for the recording medium by swinging. The information recording apparatus includes an inertia arm for restraining the swing of the actuator when the apparatus is subjected to an external shock. Here, the loading means moving of the head (slider) from the shunt position of the actuator to a position opposed to the data area of the recording medium, while the unloading means moving of the head from the position opposed to the data area to the shunt position. The swingable pivotally supported actuator generates a rotational moment when subjected to an external shock, while the inertia arm also generates a rotational moment in the same direction. The present invention restrains the swing of the actuator, when the actuator is located at least in the shunt position, by competing a rotational force generated from the actuator due to the external shock with a rotational force generated from the inertia arm, in spite of the above-mentioned shock.
A shock transmitting portion is provided on the actuator while a shock transmitting portion is also provided on the inertia arm. The transmitting portion on the actuator side and that on the inertia arm side are in a state in which they are dynamically interlocked with each other in a form of engagement or abutment with the actuator located at the shunt position.
The direction of the rotational moment of the actuator is the same as that of the inertia arm. The moving direction of the shock transmitting portion on the actuator side and that on the inertia arm side are opposite to each other. In other words, both the transmitting portions are related dynamically to each other such that both the portions are pushed to each other, or pulled from each other so that an action and a reaction work. However, this is a case where a rotational moment generates simultaneously on both the actuator and the inertia arm due to an external shock. Otherwise, when the actuator is driven to swing itself, the inertia arm generates no rotational moment, and however, the above-mentioned action and reaction do not occur on both the transmitting portions, whereby the actuator becomes possible to swing for loading and unloading with respect to the recording medium. As long as a free swing of the actuator is allowed, the relationship between both the transmitting portions is such that they may lose interlocking each other in a load and unload state, or they may interlock with each other on a condition that no substantial action and reaction occur.
Due to an external shock, a rotational moment is generated on the actuator, and the rotational moment in the same rotational direction is also generated on the inertia arm. The actuator tries to swing using the supporting axis of itself as a center with the rotational moment while the inertia arm also tries to swing using the supporting axis of itself as a center with the rotational moment.
As a result of such a trend of the swing of both the actuator and the inertia arm, the shock transmitting portion on the actuator side and that on the inertia arm side exert a rotational force on each other. The action and reaction causes the rotational forces by the both to be competed with each other.
The competing with each other causes an effect due to an external shock to be reduced. This is a function of absorbing a shock.
Therefore, when an external shock is exerted, substantially at the moment, that is, without delay in response, the function of absorbing a shock works by the above-mentioned competing with each other in rotational force. This makes it possible to prevent the actuator located at the shunt position from being swung accidentally to the recording medium side. The function absorbs a shock by instantaneously competing with each other in rotational force without delay in response, thereby allowing a positive motion without failure.
In addition to the function of absorbing a shock as described above, the crush stops is reduced with respect to preventing the actuator from excessively swinging exceeding the limit of the original swing range due to some unusual conditions such as an abnormal run of a voice coil motor.
The excessive swing of the actuator includes an aspect which excessively swings along the unloading direction from the data area of the recording medium, an aspect which excessively swings along the loading direction from the data area. This concludes, as a broader concept, that the head is swung outside the data area and further swung in a direction away from the data area. A structure for restraining the excessive swing does not use specially other members, but utilizes the inertia arm itself provided for the above-mentioned shock absorbing function.
In the actuator, a rotational force transmitting portion is provided for transmitting an excessive swing rotational force of the actuator to the inertia arm. In the inertia arm, a rotational force receiving portion is provided for receiving the rotational force from the rotational force transmitting portion on the actuator side. In addition, a swing regulating portion is provided for regulating the swing exceeding a predetermined extent of the inertia arm subjected to a rotational force at the rotational force receiving portion. The swing regulating portion can be constituted so as to share with a part of the actuator or can be constituted of a fixed portion such as an enclosure of the information recording apparatus. The sharing of the inertia arm with a part of the actuator allows the crush stops to be reduced.
When the function of restraining an excessive swing exceeding the limit of the original swing range is constituted so as to work in the unload direction of the actuator, the crush stops in the unload direction can be reduced. When it is constituted so as to function in the load direction, the crush stops in the load direction can be reduced. When it is constituted so as to function in both of the unload direction and the load direction, the two crush stops in both of the unload direction and the load direction can be reduced together.
With respect to the number of parts for the shock absorbing function, as compared to a case where two parts of the inertia lever and latch lever are used, the present invention uses one part of the inertia arm. Although there are two shock transmitting portions, they are integral with the actuator and the inertia arm, respectively. Further, the rotational force transmitting portion is integral with the actuator, while the rotational force receiving portion is integral with the inertia arm. A structure is also possible that the shock transmitting portion is shared with the rotational force transmitting portion or the rotational force receiving portion. In addition, crush stops are reduced. That is, according to the present invention, as a whole, the number of parts can be reduced and the structure can be simplified. It also contributes to making slim of the information recording apparatus. The reduced cost thereof is advantageously developed.
In the invention of the above-mentioned information recording apparatus, a preferred aspect is that the shock transmitting portion on the actuator side is shared with the rotational force transmitting portion on the above-mentioned actuator. Another preferred aspect is that the shock transmitting portion on the inertia arm side is shared with the rotational force receiving portion on the above-mentioned inertia arm. Both the shock transmitting portions exhibit the above-mentioned shock absorbing function by instantaneously competing with each other in rotational force when the actuator is located at the shunt position. The shunt position is located outside the unload direction side of the recording medium. Therefore, when the shock transmitting portions are shared with the rotational force transmitting portion and the rotational force receiving portion, the shock transmitting portions correspond to the excessive swing along the unload direction, and in this case, the crush stops in the unload direction can be reduced. Then, the sharing structure thereof allows the structure to be further simplified.
In the above-mentioned information recording apparatus, a preferred aspect is that the actuator is shared with the swing regulating portion for the above-mentioned inertia arm. When the actuator tries to excessively swing, the rotational force transmitting portion on the above-mentioned actuator side gives a rotational force to the rotational force receiving portion on the inertia arm side, whereby the actuator tries to cause the inertia arm to swing in a direction opposed to the actuator. Although the swing regulating portion regulates the swing of the inertia arm which the actuator tries to do, the actuator is shared with the swing regulating portion. Adjusting the relative positional relationship and the dimensional relationship between the actuator and the inertia arm can cause the actuator to be shared with the swing regulating portion of the inertia arm. In this case, the structure can be further simplified.
In the above-mentioned information recording apparatus, another preferred aspect is that the swing regulating portion for the above-mentioned inertia arm is used as a fixed portion in the enclosure. The fixed portion in the enclosure may be shared with a part of the enclosure itself, or another part such as a pin may be mounted onto the enclosure. In this case, the degree of freedom of design becomes relatively higher.
In the above-mentioned information recording apparatus, a preferred aspect is that the above-mentioned actuator is made a structure in which the mass is balanced as regards the supporting axis, and that the above-mentioned inertia arm is made a structure in which the mass is balanced as regards the supporting axis. A linear acceleration acts on the center of gravity. When the mass is not balanced, and the center of gravity is not coincided with the supporting axis, a linear acceleration acting on the center of gravity causes a rotational moment to be generated. Depending on the direction of the linear acceleration, the correlation between the rotational moment by the angular acceleration on the actuator and the rotational moment by the angular acceleration on the inertia arm is deviated from a predetermined relationship. Then, this causes the above-mentioned shock absorbing function by competing with each other in rotational force to have a trouble.
On the contrary, when the center of gravity is coincided with the supporting axis, no linear acceleration contributes to the rotation. Therefore, this allows the effect of the linear acceleration at shocking to be controlled as small as possible, thereby allowing the shock absorbing function by competing with each other in rotational force to be successfully exhibited satisfactorily.
In the information recording apparatus, a preferred aspect is constituted such that an inertia moment ratio (J1/J2) is substantially equal to an effective radius ratio (R1/R2).
J1 represents the inertia moment of the actuator and J2 the inertia moment of the inertia arm. R1 represents the effective radius of the shock transmitting portion on the actuator side and R2 the effective radius of the shock transmitting portion on the inertia arm side.
This allows the shock absorbing function by competing with each other in rotational force to be made ideal.
In the information recording apparatus, a preferred aspect is constituted such that the shock transmitting portion of the actuator and the shock transmitting portion of the inertia arm are engaged with each other in a state that the actuator is located at the shunt position. Another preferred aspect is constituted such that when the actuator swings in the load direction and reaches a proximate position of the data area of the recording medium, the engagement is released. In this case, a position holding mechanism is further provided for holding a position of the inertia arm at the above-mentioned engagement releasing position.
Just before the actuator becomes a loading state to the recording medium, the engagement of both shock transmitting portions are released. The actuator becomes free from the inertia arm, and thereafter the load of the swing motion of the actuator is reduced, so that a smooth swing motion of the actuator is ensured.
When the releasing is performed, the engagement must be again performed just before returning to the shunt position. The position holding mechanism holds the position of the inertia arm at the engagement releasing position, thereby allowing the re-engagement to be made positive.
In the above-mentioned description, a preferred aspect is that the above-mentioned position holding mechanism consists of an energizing device for energizing the inertia arm in a predetermined rotational direction and a fixed portion for abutting on the inertia arm at the engagement releasing position to regulate the swing. In this case, as the above-mentioned energizing device, a device consisting of a magnet and a magnetic substance for being magnetically attracted to the magnet can be included. In this case, the magnetic substance may be mounted to the inertia arm, or the magnet may be mounted to the inertia arm. Further, as the above-mentioned energizing device, a tension spring extended between the inertia arm and the fixed portion can be included.
With the regulation of the position of energizing and abutting on respect to the inertia arm, the inertia arm can be stably held at the engagement releasing position. Further, the structure thereof can be simplified.
In the above-mentioned description, a preferred aspect is that the shock transmitting portion of the above-mentioned actuator side and the shock transmitting portion of the above-mentioned inertia arm are engaged with each other in an involute form. The involute form is the most excellent for the tooth of a gear. An engagement in the involute form allows the swing of the actuator and the swing of the inertia arm when the actuator is driven, as well as the engagement and disengagement of the both to be made smooth. In addition, it allows the shock absorbing function by instantaneously competing with each other in rotational force to be made positive.
In the information recording apparatus of the present invention, the shock absorbing function by competing with each other in rotational force has been related to the function when the actuator is located at the shunt position. The description has not referred to the shock absorbing function with the actuator in a loading state to the recording medium. In the invention described below, the shock absorbing function is exhibited in loading states including that in which the head is opposite to the recording medium.
That is, in order to restrain an accidental swing of the actuator when an external shock acts on the information recording apparatus, instead of the inertia arm, there is provided an inertia substance. The inertia substance is pivotally supported revolvably and interlocked at all times with the swing in the load and unload directions of the actuator.
The inertia substance interlocked to the actuator at all times is characterized in that it exhibits the shock-absorbing function by competing with each other in rotational force in states including not only that in which the actuator is located at the shunt position, but also a loading state in which the head is opposite to the recording medium. The aspects of the interlocking at all times include abutting, contacting, meshing, link connecting and the like.
In the case of the invention previously described, the shock absorbing function by competing with each other in rotational force is made worked only at the shunt position of the actuator. In a loading state in which the head is located on the recording medium, the relationship between the actuator and the inertia arm is made released and the actuator is made swung freely independently of the inertia arm.
In this case, during the operation of the apparatus, when subjected to an external shock in a loading state in which the head is located on the recording medium, the shock causes the head arm to be vibrated on the recording medium. The floating properties of the slider for the recording medium are deteriorated. As a result a hit (that the slider hits a micro projection on the recording medium) and a crush (that a recording layer of the recording medium is subjected to a damage) can occur.
Then, it is necessary to regulate excessive swings of the actuator due to some unusual condition such as an abnormal run of a voice coil motor when the actuator is in a loading state. The excessive swings of the actuator cause the head to be moved outside the data area, and further moved in a direction away from the data area. For this a revolution regulating portion is provided for regulating the revolution range of the inertia substance.
In this case, regardless of the loading state or unloading state of the actuator, a rotational moment in the same direction acts always on both the actuator and the inertia substance for an external shock. As a result rotational forces on both the interlocking portions always compete with each other and the external force is absorbed.
Therefore, when the actuator stays at the shunt position, an accidental swing in the load direction of the actuator can be prevented. Also when the actuator is in a loading state, competing with each other in rotational force at all times on the interlocking portions absorbs the shock against the external shock. This allows the floating properties of the slider to be prevented from being deteriorated, with a result that a damage to the recording medium can be avoided.
In addition, the revolution range of the inertia substance is regulated with a revolution regulating portion for the inertia substance to cope with the excessive moving of the actuator in the load and unload directions. The revolving position of the actuator in the load direction and/or unload direction can be regulated. The crush stop in the load direction and/or the unload direction can be reduced.
In the information recording apparatus having the revolution regulating portion for the inertia substance, a preferred aspect is that the inertia substance is constituted of a disc-shaped frictional resistance substance. Another preferred aspect is that fixed to the actuator is a disc-shaped frictional resistance substance using the supporting axis as a center, and these two frictional resistance substances are constituted such that they abut on each other at all times to absorb the shock by frictional force.
The shock absorbing function by instantaneously competing with each other in rotational force is realized effectively with the frictional resistance.
Further, another preferred aspect is that the inertia substance is constituted of a gear, another gear is fixed to actuator using the supporting axis as a center, and these two gears are constituted such that they mesh with each other at all times to absorb the shock by frictional force. The shock-absorbing function by competing with each other in rotational force is realized effectively with the mesh of gears with each other.
In the above-mentioned description, a preferred aspect is that the revolution regulating portion for the above-mentioned inertia substance is a fixed portion in the enclosure, and a notch portion engaging with the fixed portion is formed on the peripheral surface of the inertia substance.
Although the above-mentioned fixed portion includes a pin-shaped one, compared to the pin, the notch portion is relatively displaceable and, however, when the end edge of the notch portion abuts on the pin, a further revolving of the inertia substance is regulated.
The above-mentioned inertia substance is preferably mass balanced as regards the supporting axis thereof. The substance having the notch portion is also preferably mass balanced. This allows an effect of a linear acceleration on the rotation to be avoided, and the shock absorbing function by competing with each other in rotational force at all times to be successfully exhibited satisfactorily.
Further, in the information recording apparatus having the inertia substance, a preferred aspect is constituted such that the inertia moment ratio (J1/J2) is substantially equal to the effective radius ratio (R1/R2). This allows the shock absorbing function by competing with each other in rotational force at all times to be made ideal.
The invention of the information recording apparatus having the above-mentioned inertia substance may include an aspect which has the inertia substance, and however, omits the revolution regulating portion for the inertia substance. The principal object is not only to exhibit the shock absorbing function by competing with each other in rotational force at all times, that is, the shunt position, but also to exhibit the shock absorbing function by competing with each other in rotational force even in loading state. In this case, it does not matter whether the crush stop is provided or not, and thus the crush stop may be provided without omitting it, and even when omitting it, means corresponding to the crush stop may be separately provided.
In the present invention on the above-mentioned information recording apparatus, it does not matter whether a specific aspect of the recording medium is considered or not, and thus a disc-shaped recording medium may be intended, or a card-shaped recording medium may be intended. However, the present invention preferably intends for the disc-shaped recording medium.
Further, although the present invention intends for an information recording apparatus, it does not matter whether a specific aspect of the information recording apparatus is considered or not, and thus a magnetic recording apparatus, a magneto-optic recording apparatus or an optical recording apparatus may be appropriate. However, the present invention preferably intends for the magnetic disc apparatus. In this case, a head for the above-mentioned recording/reproducing is a magnetic head.